Different organisms often inhabit different environments. From studies of modern and ancient traces, some traces (or groups and associations of traces) have been determined to indicate a variety of environmental parameters (salinity, water depth, current/wave energy, oxygen level, etc.), so are useful for interpreting ancient environments of deposition. Ichnofacies were originally defined based on bathymetric depth (Seilacher, 1964, 1967), but subsequent research found that changes in oxygen level or other parameters could form similar associations at shallower depths than originally inferred (e.g., Ekdale and others, 1984). A variety of ichnofacies have since been interpreted based on a variety of parameters (e.g., Bottjer and others, 1987; Knaust and Bromley, 2012).

In Kentucky, a unit where the relationship between ichnofacies and relative paleobathymetry seems to work well is the Borden Formation. The Borden Formation is a Lower to Middle Mississippian unit formed by the offshore part of deltas prograding westward from a paleocoastline in Virginia and West Virginia. Chaplin (1980) examined trace fossils and trace fossil associations in the Borden, and showed different units had different types and abundances of traces relative to their inferred paleobathymetry in a deltaic facies model.

Example of ichnofacies from the Borden Formation in eastern Kentucky.
Example of ichnofacies from the Borden Formation in eastern Kentucky. The abundance of individual trace fossils is shown by the width of vertical bars through four members of the Borden Formation. Trace fossils show changes in type, diversity, and relative abundance in the four units. Associations of the most common trace fossils in the different units are combined into ichnofacies. Note some trace fossils are shared in different ichnofacies. Data from Chaplin (1980).

Click here for a pdf copy of Chaplin’s 1980 guide to the trace fossils of the Borden Formation in eastern Kentucky https://kgs.uky.edu/kgsweb/olops/pub/kgs/GBGSK80.pdf



Behaviors recorded by traces (ethology)

Where traces occur in rock beds (stratinomy, toponomy)


Other types of traces (borings, excrement, rooting)

Bioturbation intensity and ichnofabric

Some Kentucky trace fossils

References cited



Last Modified on 2023-01-05
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